20290-99-7 6,8-Dioxabicyclo(3.2.1)octane, 7-ethyl-5-methyl-, (1R-exo)- (8CI)(9CI) 7-Ethyl-5-methyl-6,8-dioxabicyclo(3.2.1)octane Brevicomin NSC 154758 exo-Brevicomin